A United Nations Security Council resolution gives Sudan until the end of this month to quell violence in the western region of Darfur, or face possible economic and diplomatic penalties. Experts at a talk sponsored by the Johns Hopkins University School of Advanced International Studies say the situation in Darfur is worse than reported by the Sudanese government. Clashes in the Sudanese region of Darfur, between rebel groups and government-backed militias, known as the Janjaweed, have already killed tens of thousands of civilians and displaced more than one million others.

The U.N. Security Council passed a resolution on Darfur at the end of July. At about the same time, the U.N. representative for Internally Displaced Persons, Francis Deng, visited Sudan.

"We were told by the authorities in Khartoum and in Darfur that the security situation had considerably improved and that people were being encouraged to go back," he said. "Actually, they said people were going back voluntarily because it was now safe in their villages to go back."

Mr. Deng said the displaced people he spoke with in Darfur had a starkly different story, about the reality of a situation that has not improved.

"People said that insecurity had not gone entirely," he added. "That while the camps, themselves, were quite secure, venturing outside the camps exposed people to attacks and killings and even rape. And people were therefore reluctant to go back to their villages. Even though in principle, they expressed interest in eventually returning, but they didn't think it was safe to go back as yet."

John Prendergast, from the International Crisis Group, said the Sudanese government has lifted many bureaucratic restrictions that had hampered the efforts of non-governmental groups in Darfur. But he says continuing violence is also still the main constraint to international aid work.

"We have continuing insecurity, and that's as a result, and we've seen the results come across our desk with deadening regularity, of government and Janjaweed attacks against civilian populations," said Mr. Prendergast. "Even two days ago, a horrible attack was once again [happening]. And then, we also have less frequent, but serious, rebel ambushes, that need to be addressed as well."

Mr. Prendergast criticizes the international community for providing less than half of a March U.N. appeal for $350 million in humanitarian aid for Darfur, and for acting too slowly to stop Darfur's death toll from mounting.

"As high-level officials from all over the world continue to talk very passionately, but act very timidly in Darfur, the Darfurian people continue to perish. And we're going to see those numbers increase dramatically," he added.

Mr. Prendergast says even if the violence is reduced, the growing prevalence of epidemics like water-borne diseases will continue to kill people.